The present invention relates generally to aircraft galleys that include beverage and food cart storage compartments, and more particularly to a system to shut off the chilling system to the storage compartments when the compartment door is open to prevent moisture and warm air from entering the chilling unit.
Modern large commercial passenger carrying airplanes typically employ one of two methods for keeping perishable food stuffs and non-perishable drinks at temperatures capable of prolonging their usability and/or increasing their enjoyment, during short haul, long haul or ultra long haul aircraft journeys, where in-flight catering services are offered. The first method utilizes a vapor cycle cooling system having air chillers that utilize a conventional refrigerant gas compression and expansion operation to generate a secondary re-circulated chilled air loop. The chilled air is generally supplied and returned via thermally insulated air ducting to and from a suitable storage structure, such as a galley. The air chiller may be located on or in the galley, or mounted in part of the aircraft airframe.
The second method utilizes the same conventional refrigerant gas compression and expansion operation, but the cooling medium produced is a chilled liquid that is pumped in a closed loop to and from a suitable storage structure such as a galley. The chilled liquid may either be configured as: (1) a large centralized system for the whole aircraft; (2) be based at each separate aircraft door galley complex forming a local area chilling loop; or (3) be based on each individual galley as a standalone system. Within the galley, the liquid is passed, via a control valve and electronic control system, to a heat exchanger where an electric axial (or other) fan blows or sucks air through its matrix and around and enclosed areas of the storage structure that requires chilling, for example: a galley cart bay or compartment.
Both systems require that the closed areas of the storage structure, such as the bays that house the beverage carts, receive cooled air for as long as possible to maintain the required temperature. However, when the cart bay doors are left open for prolonged periods of time, the closed area is exposed to ambient air from the external galley area. Moisture from the ambient air can cause the evaporator within the chilling system to freeze and stop working, i.e., cut off the flow of air. With the chilling system not working, food cart temperatures can rise to unacceptable levels, which could result in the contents becoming hazardous to health.